Cop Mirjan Lolja, assigned to the 25th precinct in East Harlem, spotted himself on surveillance video that police released from the attack, and turned himself in Wednesday night at the stationhouse, sources said.

That video shows a grinning man walking through a turnstile at the East Tremont station where the 28-year-old victim was tackled from behind and choked on the floor around 2:30 a.m. Dec. 23.

The conductor was on the platform helping riders navigate a service diversion when he began to argue with her, sources said.

She tried to walk away — but the man bear hugged her, shoved her to the floor and wrapped his arms around her neck before another conductor pulled him off of her, sources said.

The victim was treated for head, neck, and back injuries.

“We’re always attacked by the public,” said Joe Costales, a chair at the Transport Workers Union Local 100. “It’s just outrageous that this attack happened by an off-duty officer.”

Lolja has been suspended without pay, and the NYPD’s Internal Affairs Bureau is investigating, sources said.